We further analyze the performance of our method (MS-STS VIS) under three specific challenging scenarios: fast motion, target size change (scale variation) and aspect-ratio change. To this end, we classified the videos into three categories: (i) fast motion of the object, (ii) object size changes, and (iii) aspect-ratio changes. In particular, we follow the well-established VOT-2015 benchmark [1]} to label a particular video from above categories as follows:
(i)
fast motion: if object center in current frame moves by at least 30% of its size in previous frame.
(ii) change in object size: if the ratio of the maximum size to the minimum size of an object in the video is greater than 1.5. (iii)
change in aspect-ratio: if the ratio of the maximum to the minimum aspect (width/height) of the bounding box enclosing an object in the video is greater than 1.5.
